Ensia: When tropical ecologist Greg Asner glances down at the Amazon tree canopy from the window of his twin-engine plane, he sees more than indeterminate treetops punctuated by looping rivers and bright bursts of flowers.
With a spectrometer mounted in a shiny gold canister behind him, he is fingerprinting individual tree species in an effort to draw the first large-scale biodiversity map of the worlds biggest expanse of tropical forest.
Scientists know the Amazon is astoundingly diverse, but...